Fix typos in comments of JSCJSValue.h

https://bugs.webkit.org/show_bug.cgi?id=270775

Reviewed by Keith Miller.

It is the second bit which is set for non-numeric immediates and the second bit is bit 1.

* Source/JavaScriptCore/runtime/JSCJSValue.h:

Canonical link: https://commits.webkit.org/275951@main

Source/JavaScriptCore/runtime/JSCJSValue.h

@@ -423,7 +423,7 @@ class JSValue {
      * ranges to encode other values (however there are also other ranges of NaN space that
      * could have been selected).
      *
-     * This range of NaN space is represented by 64-bit numbers begining with the 15-bit
+     * This range of NaN space is represented by 64-bit numbers beginning with the 15-bit
      * hex patterns 0xFFFC and 0xFFFE - we rely on the fact that no valid double-precision
      * numbers will fall in these ranges.
      *
@@ -452,9 +452,9 @@ class JSValue {
      *     Null:      0x02
      *
      * These values have the following properties:
-     * - Bit 1 (OtherTag) is set for all four values, allowing real pointers to be
+     * - Bit 1 (0-indexed) is set (OtherTag) for all four values, allowing real pointers to be
      *   quickly distinguished from all immediate values, including these invalid pointers.
-     * - With bit 3 masked out (UndefinedTag), Undefined and Null share the
+     * - With bit 3 (0-indexed) masked out (UndefinedTag), Undefined and Null share the
      *   same value, allowing null & undefined to be quickly detected.
      *
      * No valid JSValue will have the bit pattern 0x0, this is used to represent array
@@ -482,7 +482,7 @@ class JSValue {
     static_assert(LowestOfHighBits & NumberTag);
     static_assert(!((LowestOfHighBits>>1) & NumberTag));
 
-    // All non-numeric (bool, null, undefined) immediates have bit 2 set.
+    // All non-numeric (bool, null, undefined) immediates have bit 1 (0-indexed) set.
     static constexpr int32_t OtherTag       = 0x2;
     static constexpr int32_t BoolTag        = 0x4;
     static constexpr int32_t UndefinedTag   = 0x8;